Background: It has been suggested that, in order to validate a diagnosis of (C)APD (central auditory
processing disorder), testing using direct cross-modal analogs should be performed
to demonstrate that deficits exist solely or primarily in the auditory modality (McFarland
and Cacace, 1995; Cacace and McFarland, 2005). This modality-specific viewpoint is
controversial and not universally accepted (American Speech-Language-Hearing Association
[ASHA], 2005; Musiek et al, 2005). Further, no such analogs have been developed to
date, and neither the feasibility of such testing in normally functioning individuals
nor the concurrent validity of cross-modal analogs has been established.
Purpose: The purpose of this study was to investigate the feasibility of cross-modal testing
by examining the performance of normal adults and children on four tests of central
auditory function and their corresponding visual analogs. In addition, this study
investigated the degree to which concurrent validity of auditory and visual versions
of these tests could be demonstrated.
Research Design: An experimental repeated measures design was employed.
Study Sample: Participants consisted of two groups (adults, n = 10; children, n = 10) with normal
and symmetrical hearing sensitivity, normal or corrected-to-normal visual acuity,
and no family or personal history of auditory/otologic, language, learning, neurologic,
or related disorders.
Data Collection and Analysis: Visual analogs of four tests in common clinical use for the diagnosis of (C)APD were
developed (Dichotic Digits [Musiek, 1983]; Frequency Patterns [Pinheiro and Ptacek,
1971]; Duration Patterns [Pinheiro and Musiek, 1985]; and the Random Gap Detection
Test [RGDT; Keith, 2000]). Participants underwent two 1 hr test sessions separated
by at least 1 wk. Order of sessions (auditory, visual) and tests within each session
were counterbalanced across participants. ANOVAs (analyses of variance) were used
to examine effects of group, modality, and laterality (for the Dichotic/Dichoptic
Digits tests) or response condition (for the auditory and visual Frequency Patterns
and Duration Patterns tests). Pearson product-moment correlations were used to investigate
relationships between auditory and visual performance.
Results: Adults performed significantly better than children on the Dichotic/Dichoptic Digits
tests. Results also revealed a significant effect of modality, with auditory better
than visual, and a significant modality × laterality interaction, with a right-ear
advantage seen for the auditory task and a left-visual-field advantage seen for the
visual task. For the Frequency Patterns test and its visual analog, results revealed
a significant modality × response condition interaction, with humming better than
labeling for the auditory version but the reversed effect for the visual version.
For Duration Patterns testing, visual performance was significantly poorer than auditory
performance. Due to poor test-retest reliability and ceiling effects for the auditory
and visual gap-detection tasks, analyses could not be performed. No cross-modal correlations
were observed for any test.
Conclusions: Results demonstrated that cross-modal testing is at least feasible using easily accessible
computer hardware and software. The lack of any cross-modal correlations suggests
independent processing mechanisms for auditory and visual versions of each task. Examination
of performance in individuals with central auditory and pan-sensory disorders is needed
to determine the utility of cross-modal analogs in the differential diagnosis of (C)APD.
Key Words
Central auditory processing - dichoptic - dichotic - gap detection - modality specificity
- temporal patterning
